101 lines
3.3 KiB
C
101 lines
3.3 KiB
C
#include <assert.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
#include "common.h"
|
|
#include "receive.h"
|
|
#include "airspy_adsb.h"
|
|
|
|
struct __attribute__((packed)) airspy_adsb_common_overlay {
|
|
char mlat_timestamp[8];
|
|
char semicolon1;
|
|
char mlat_precision[2];
|
|
char semicolon2;
|
|
char rssi[4];
|
|
char semicolon3;
|
|
};
|
|
|
|
struct __attribute__((packed)) airspy_adsb_mode_s_short_overlay {
|
|
char asterisk;
|
|
char payload[14];
|
|
char semicolon;
|
|
struct airspy_adsb_common_overlay common;
|
|
char cr;
|
|
char lf;
|
|
};
|
|
|
|
struct __attribute__((packed)) airspy_adsb_mode_s_long_overlay {
|
|
char asterisk;
|
|
char payload[28];
|
|
char semicolon;
|
|
struct airspy_adsb_common_overlay common;
|
|
char cr;
|
|
char lf;
|
|
};
|
|
|
|
struct airspy_adsb_parser_state {
|
|
struct mlat_state mlat_state;
|
|
};
|
|
|
|
static bool airspy_adsb_parse_common(const struct airspy_adsb_common_overlay *overlay, struct packet *packet, struct airspy_adsb_parser_state *state) {
|
|
if (overlay->semicolon1 != ';' ||
|
|
overlay->semicolon2 != ';' ||
|
|
overlay->semicolon3 != ';') {
|
|
return false;
|
|
}
|
|
uint16_t mlat_mhz = 2 * hex_to_int(overlay->mlat_precision, sizeof(overlay->mlat_precision) / 2);
|
|
packet->mlat_timestamp = mlat_timestamp_scale_in(hex_to_int(overlay->mlat_timestamp, sizeof(overlay->mlat_timestamp) / 2), UINT32_MAX, mlat_mhz, &state->mlat_state);
|
|
packet->rssi = rssi_scale_in(hex_to_int(overlay->rssi, sizeof(overlay->rssi) / 2), UINT16_MAX);
|
|
return true;
|
|
}
|
|
|
|
static bool airspy_adsb_parse_mode_s_short(struct buf *buf, struct packet *packet, struct airspy_adsb_parser_state *state) {
|
|
struct airspy_adsb_mode_s_short_overlay *short_overlay = (struct airspy_adsb_mode_s_short_overlay *) buf_at(buf, 0);
|
|
if (buf->length < sizeof(*short_overlay) ||
|
|
short_overlay->asterisk != '*' ||
|
|
short_overlay->semicolon != ';' ||
|
|
short_overlay->cr != '\r' ||
|
|
short_overlay->lf != '\n') {
|
|
return false;
|
|
}
|
|
if (!airspy_adsb_parse_common(&short_overlay->common, packet, state)) {
|
|
return false;
|
|
}
|
|
packet->type = MODE_S_SHORT;
|
|
hex_to_bin(packet->payload, short_overlay->payload, sizeof(short_overlay->payload) / 2);
|
|
buf_consume(buf, sizeof(*short_overlay));
|
|
return true;
|
|
}
|
|
|
|
static bool airspy_adsb_parse_mode_s_long(struct buf *buf, struct packet *packet, struct airspy_adsb_parser_state *state) {
|
|
struct airspy_adsb_mode_s_long_overlay *long_overlay = (struct airspy_adsb_mode_s_long_overlay *) buf_at(buf, 0);
|
|
if (buf->length < sizeof(*long_overlay) ||
|
|
long_overlay->asterisk != '*' ||
|
|
long_overlay->semicolon != ';' ||
|
|
long_overlay->cr != '\r' ||
|
|
long_overlay->lf != '\n') {
|
|
return false;
|
|
}
|
|
if (!airspy_adsb_parse_common(&long_overlay->common, packet, state)) {
|
|
return false;
|
|
}
|
|
packet->type = MODE_S_LONG;
|
|
hex_to_bin(packet->payload, long_overlay->payload, sizeof(long_overlay->payload) / 2);
|
|
buf_consume(buf, sizeof(*long_overlay));
|
|
return true;
|
|
}
|
|
|
|
void airspy_adsb_init() {
|
|
assert(sizeof(struct airspy_adsb_parser_state) <= PARSER_STATE_LEN);
|
|
assert(sizeof(struct airspy_adsb_mode_s_short_overlay) < BUF_LEN_MAX);
|
|
assert(sizeof(struct airspy_adsb_mode_s_long_overlay) < BUF_LEN_MAX);
|
|
}
|
|
|
|
bool airspy_adsb_parse(struct buf *buf, struct packet *packet, void *state_in) {
|
|
struct airspy_adsb_parser_state *state = (struct airspy_adsb_parser_state *) state_in;
|
|
|
|
return (
|
|
airspy_adsb_parse_mode_s_short(buf, packet, state) ||
|
|
airspy_adsb_parse_mode_s_long(buf, packet, state));
|
|
}
|